1. Field of the Invention
The present invention relates generally to the adjustment mechanism that regulates the anchoring angle of the rear supporting beam of a treadmill, and more particularly to an anchoring angle of a rear support beam that can be fine-tuned in order to provide flexible slanting angles to the treadmill frame.
2. Description of the Prior Art
FIG. 1 shows a prior art disclosed in U.S. Pat. No. 5,607,375, which is currently the most widely used adjustment mechanism for the anchoring angle on the rear supporting beam of a treadmill. The drawings reveal that it primarily concerns placing a brake piece 11 atop the rear supporting beam 10 thereof, the opposite side from the brake piece 11 is equipped with several incremental slanted stop notches 12. The mechanism of a connecting axle 13 is connected to supporting board 15 located at the bottom surface of the treadmill frame 14. Thereafter, the lower side of the supporting board 15 is equipped with a stop piece 17 via a transmission axle 16, while the axial beam 18 beneath that stop piece 17 is equipped with a hooked spring 20 to the corresponding axial beam 19 on the supporting board 15. At this time, the top part 171 of the stop piece 17 will engage with any slanted notch 12 on the brake piece 11 and remain in a stationary position. Therefore, when the slant angle of the treadmill frame 14 has to be adjusted, it only requires one to lift the treadmill frame 14, while the weight of the rear supporting beam 10 will automatically rotate around the connecting axle 13 to drop downward. Right now, the position of slanted notch 12 on the other side of the brake piece 11 will follow to shift upwardly so that the top part 171 of the stop piece 17 falls on the next slanted notch 12 to modify the anchoring angle of the rear supporting beam, and to further modify the slant angle of the treadmill frame 14.
However, although this structural design is deemed as convenient, in actual application the position of the slanted notches 12 on the brake piece 11 and the number of increments are fixed, thus its anchoring angle's changes are extremely limited, and may not meet the user's demands.